BRITISH police have arrived in Turkey as the search continues for three missing schoolgirls believed to have fled to Syria to join Islamic State.

Officers are working closely with the Turkish authorities who are providing a great deal of assistance and support to our investigation.

New Scotland Yard spokesman

Relatives of Shamima Begum, 15, Kadiza Sultana, 16, and 15-year-old Amira Abase, have issued heartfelt pleas for the youngsters to come home amid fears they may have been recruited by jihadists online.

The girls, who were "straight A students" at Bethnal Green Academy in east London, boarded a flight from Gatwick Airport to Istanbul in Turkey on Tuesday.

A Scotland Yard spokesman said its officers were in Turkey but refused to confirm whether they were involved in the search for the girls.

"Officers are working closely with the Turkish authorities who are providing a great deal of assistance and support to our investigation," he said.

Questions have been raised about what contact the girls may have had with extremists after a tweet, sent from a Twitter account under the name Shamima Begum, was sent to Aqsa Mahmood, who left Glasgow for Syria to be a "jihadi bride" in 2013.

Shamima's older sister Renu Begum, 27, said any attempt by extremists to prey on the "vulnerable" youngsters was "cruel" and "evil".

In a statement released through their lawyer Aamer Anwar, Ms Mahmood's family said they were "full of horror and anger" that she may have had a role to play in "the recruitment of these young girls to Isis".

Speaking at Scotland Yard's headquarters, Ms Begum said her "baby" sister Shamima did not show any signs she was planning to travel abroad and broke down in tears as she urged her to return home.

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The families of Amira Abase and Shamima Begum are desperate for their return

Shamima was last seen by her mother on Tuesday morning as she boarded a bus after claiming she was going to extra classes at school.

Clutching her missing sister's pyjamas, Ms Begum said: "Please come home. Mum needs you more than anything in the world. You're our baby. We just want you home. We want you safe."

Ms Begum said she hoped her sister had gone with the intention of bringing back another 15-year-old girl from Bethnal Green Academy who went to Syria in December.

"She's a sensible girl," she said. "We're hoping she wouldn't do anything that would put her in any danger.

"It's left a big hole in the house.

"Her family love her more than anybody else in this world can. If anyone is telling her they're going to love her more than us, they're wrong.

"She's a clever girl but she's only young and young minds can easily be swayed."

She added: "To convince young children, young girls who are highly intelligent ... at that age, who are vulnerable, it's just wrong. It's a really evil thing to do. You're breaking up entire families."

Mr Hussen said his daughter had never spoken about an interest in jihad with him but "maybe with friends".

"She doesn't dare discuss something like this with us," he added. "She knows what the answer would be."

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The three missing teenagers caught on CCTv at Gatwick

Mr Hussen said his wife had a "broken heart".

"If anyone doesn't have hope, life would be miserable," he said. "We don't despair. We struggle. It's stressful. We hope, of course."

Reading a message to Kadiza, her older sister Halima Khanom said: "We want you to know that we all miss you and we love you.

"Everyone is hurting because we don't know if you are safe, especially mum.

"Find the courage in your heart to contact us and let us know how you are and if you are okay. That is all we ask."

The search continued as it was reported today that British counterterrorism police were on alert last night after a militant Islamic group urged Muslims to attack Oxford Street and two shopping centres in London.

• Anyone with information about the missing teens is urged to call the Anti-Terrorist Hotline number on 0800 789 321